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Chromosome Deletion Notation in Cancers

Chromosome Deletion Notation in Cancers


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The cancer literature often refers to the deletion of certain sections of a chromosome (e.g. "17p del" or "Del(17p)" for the deletion of chromosome 17's p-arm.)

Does this mean both alleles of the chromosome were deleted for the specified cytoband (i.e., copy number analysis would show zero in this case)? Or does it mean one of the alleles was deleted, and thus one remains (copy number analysis would show a copy number of 1 in this case)?

Thanks


9q22.3 microdeletion

9q22.3 microdeletion is a chromosomal change in which a small piece of chromosome 9 is deleted in each cell. The deletion occurs on the long (q) arm of the chromosome in a region designated q22.3. This chromosomal change is associated with delayed development, intellectual disability, certain physical abnormalities, and the characteristic features of a genetic condition called Gorlin syndrome.

Many individuals with a 9q22.3 microdeletion have delayed development, particularly affecting the development of motor skills such as sitting, standing, and walking. In some people, the delays are temporary and improve in childhood. More severely affected individuals have permanent developmental disabilities along with intellectual impairment and learning problems. Rarely, seizures have been reported in people with a 9q22.3 microdeletion.

About 20 percent of people with a 9q22.3 microdeletion experience overgrowth (macrosomia), which results in increased height and weight compared to unaffected peers. The macrosomia often begins before birth and continues into childhood. Other physical changes that are sometimes associated with a 9q22.3 microdeletion include the premature fusion of certain bones in the skull (metopic craniosynostosis) and a buildup of fluid in the brain (hydrocephalus). Affected individuals can also have distinctive facial features such as a prominent forehead with vertical skin creases, upward- or downward-slanting eyes, a short nose, and a long space between the nose and upper lip (philtrum).

9q22.3 microdeletions also cause the characteristic features of Gorlin syndrome (also known as nevoid basal cell carcinoma syndrome). This genetic condition affects many areas of the body and increases the risk of developing various cancerous and noncancerous tumors. In people with Gorlin syndrome, the type of cancer diagnosed most often is basal cell carcinoma , which is the most common form of skin cancer. Most people with this condition also develop noncancerous (benign) tumors of the jaw, called keratocystic odontogenic tumors, which can cause facial swelling and tooth displacement. Other types of tumors that occur in some people with Gorlin syndrome include a form of childhood brain cancer called a medulloblastoma and a type of benign tumor called a fibroma that occurs in the heart or in a woman's ovaries. Other features of Gorlin syndrome include small depressions (pits) in the skin of the palms of the hands and soles of the feet an unusually large head size (macrocephaly ) with a prominent forehead and skeletal abnormalities involving the spine, ribs, or skull.


Cytogenetic location

Geneticists use a standardized way of describing a gene's cytogenetic location. In most cases, the location describes the position of a particular band on a stained chromosome:

It can also be written as a range of bands, if less is known about the exact location:

The combination of numbers and letters provide a gene's “address” on a chromosome. This address is made up of several parts:

The chromosome on which the gene can be found. The first number or letter used to describe a gene's location represents the chromosome. Chromosomes 1 through 22 (the autosomes) are designated by their chromosome number. The sex chromosomes are designated by X or Y.

The arm of the chromosome. Each chromosome is divided into two sections (arms) based on the location of a narrowing (constriction) called the centromere. By convention, the shorter arm is called p, and the longer arm is called q. The chromosome arm is the second part of the gene's address. For example, 5q is the long arm of chromosome 5, and Xp is the short arm of the X chromosome.

The position of the gene on the p or q arm. The position of a gene is based on a distinctive pattern of light and dark bands that appear when the chromosome is stained in a certain way. The position is usually designated by two digits (representing a region and a band), which are sometimes followed by a decimal point and one or more additional digits (representing sub-bands within a light or dark area). The number indicating the gene position increases with distance from the centromere. For example: 14q21 represents position 21 on the long arm of chromosome 14. 14q21 is closer to the centromere than 14q22.

Sometimes, the abbreviations “cen” or “ter” are also used to describe a gene's cytogenetic location. “Cen” indicates that the gene is very close to the centromere. For example, 16pcen refers to the short arm of chromosome 16 near the centromere. “Ter” stands for terminus, which indicates that the gene is very close to the end of the p or q arm. For example, 14qter refers to the tip of the long arm, or the very end, of chromosome 14.

The CFTR gene is located on the long arm of chromosome 7 at position 7q31.2.


Chromosome Map

Our genetic information is stored in 23 pairs of chromosomes that vary widely in size and shape. Chromosome 1 is the largest and is over three times bigger than chromosome 22. The 23rd pair of chromosomes are two special chromosomes, X and Y, that determine our sex. Females have a pair of X chromosomes (46, XX), whereas males have one X and one Y chromosomes (46, XY). Chromosomes are made of DNA, and genes are special units of chromosomal DNA. Each chromosome is a very long molecule, so it needs to be wrapped tightly around proteins for efficient packaging.

Near the center of each chromosome is its centromere, a narrow region that divides the chromosome into a long arm (q) and a short arm (p). We can further divide the chromosomes using special stains that produce stripes known as a banding pattern. Each chromosome has a distinct banding pattern, and each band is numbered to help identify a particular region of a chromosome. This method of mapping a gene to a particular band of the chromosome is called cytogenetic mapping. For example, the hemoglobin beta gene (HBB) is found on chromosome 11p15.4. This means that the HBB gene lies on the short arm (p) of chromosome 11 and is found at the band labeled 15.4.

With the advent of new techniques in DNA analysis, we are able to look at the chromosome in much greater detail. Whereas cytogenetic mapping gives a bird's eye view of the chromosome, more modern methods show DNA at a much higher resolution. The Human Genome Project aims to identify and sequence the


Chromosome Deletion Notation in Cancers - Biology

Source: image on left from the GeneMap'99 illustration of Chromosome 18. Image on right from the CCAP Web page on "Recurrent Aberration Data."

Each chromosome arm is divided into regions, or cytogenetic bands, that can be seen using a microscope and special stains. The cytogenetic bands are labeled p1, p2, p3, q1, q2, q3, etc., counting from the centromere out toward the telomeres. At higher resolutions, sub-bands can be seen within the bands. The sub-bands are also numbered from the centromere out toward the telomere.

For example, the cytogenetic map location of the CFTR gene is 7q31.2, which indicates it is on chromosome 7, q arm, band 3, sub-band 1, and sub-sub-band 2.

The ends of the chromosomes are labeled ptel and qtel. For example, the notation 7qtel refers to the end of the long arm of chromosome 7.

Strachan, T. and Read, A.P. 1999. Human Molecular Genetics, 2nd ed. New York: John Wiley & Sons.

GeneMap'99 (click on a chromosome number).

The CCAP Web page on "Recurrent Aberration Data" (click on a chromosome number), based on a genome-wide map of chromosomal breakpoints in human cancer by Drs. Mitelman, Mertens, and Johansson.


Coding DNA Reference Sequence

Problems in colloquial CFTR mutation nomenclature reside mainly in the numbering of nucleotide positions. Although the colloquial notations of CFTR mutations are also based on the GenBank cDNA reference sequence <"type":"entrez-nucleotide","attrs":<"text":"NM_000492.3","term_id":"90421312","term_text":"NM_000492.3">> NM_000492.3, the colloquial notations use nucleotide numbering with the A of the ATG initiation codon at the nucleotide number 133. One can retrieve the coding DNA sequence (�S”) for CFTR simply by clicking on the CDS link in GenBank <"type":"entrez-nucleotide","attrs":<"text":"NM_000492.3","term_id":"90421312","term_text":"NM_000492.3">> NM_000492.3 this opens a window in which the nucleotide numbering starts with ʱ at the A of the ATG initiation codon, thus eliminating 132 nucleotides from the 5′-UTR. There is only one coding DNA reference sequence for a given GenBank accession number, so that one can describe nucleotide positions unequivocally.


Biological Significance of 5q Deletion in Hemato-poiesis and Bone Marrow Function

MDS are clonal hematopoietic stem cell disorders characterized clinically by ineffective hematopoiesis as a consequence of abnormalities in proliferation, differentiation, and apoptosis of hematopoietic precursors and their progeny. These disorders are typically more prevalent in the elderly with the median age at diagnosis between 60 and 80 years (3, 20–22). Overall, the clinical picture includes peripheral cytopenias in the setting of normocellular or hypercellular bone marrow and increased risk of transformation to AML. Hypocellular bone marrow is less common in MDS. A summary of the clinical and hematologic features that are specific to the 5q− syndrome subtype of MDS is shown in Fig. 1 (11, 13, 15, 22). Bone marrow features associated with 5q− syndrome include hypolobulated megakaryocytes, erythroid hypoplasia, and <5% blasts.

Clinical and pathologic characteristics of 5q− syndrome.

Role of tumor suppressor genes in MDS pathogenesis. Chromosome 5q contains many genes that are involved in the regulation of hematopoiesis, including cytokines and their receptors, cell cycle regulators, transcription factors, and signaling mediators. The clustering of hematologic genes between 5q13 and 5q33 suggests a correlation between the genetic abnormality and the clinical features of 5q− syndrome and other del(5q) MDS subtypes (19, 23).

The prevalence of 5q deletions in patients with MDS raises the possibility of a tumor suppressor gene on the long arm of chromosome 5, the loss of which is the basic event leading to disease progression. Efforts to localize such a gene has resulted in the identification of critical, minimally deleted regions (24–26). In 5q− syndrome, the critical region of gene loss has been defined as a 1.5 Mb region at 5q31-q32 flanked by D5S413 and the GLRA1 gene (25, 26). Many genes have been mapped to this region, as evidenced by a review of the Online Mendelian Inheritance in Man database of the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/Omim/getmap.cgi?). Table 1 shows a selection of genes localized on the commonly deleted segment of chromosome 5 in the 5q− syndrome. This region is distinct from and distal to a 1.5 Mb region at 5q31.1 flanked by the genes IL-9 and EGR-1 and deleted in AML and other forms of MDS involving 5q deletions (24, 27). The specification of two separate genomic intervals on chromosome 5q implies that a different gene or group of genes contributes to the pathogenesis of these different myeloid disorders. These findings are consistent with categorizing 5q− syndrome as a distinct subtype of MDS with a different pathogenesis than other forms of MDS involving 5q deletions (28).

Selected genes localized in chromosome 5 (q31-q33)

To date, no single tumor suppressor gene responsible for MDS on chromosome 5q has been identified. Although there are a number of interesting candidates (e.g., MEGF1 and G3BP), none have yet been shown to be critical for disease progression (19, 28). Given the large size of the 5q deletions often occurring in MDS and the absence of a clear candidate gene, it is possible that one of several genes could result in MDS. An alternate possibility is a gene dosage effect caused by deletion of multiple genes contained in the 5q region, which are functionally related to hematopoiesis.

Clonal basis of disease in 5q− syndrome. The frequency of 5q deletions, as well as other chromosomal abnormalities in MDS, indicates that these abnormalities are not random events but rather reflect the clonal evolution and multistep pathogenesis of MDS (21, 29). According to a multistep model, initiating or “primary” genetic lesions, which may be acquired or caused by spontaneous mutation, within a hematopoietic stem cell promote the acquisition of “secondary” genetic events, characterized by stepwise losses and/or gains of specific chromosomal regions (e.g., 5q−, −7, or +8 ref. 29). These secondary genetic alterations may affect cell cycle control, transcription, and/or tumor suppressor activity, providing the MDS clone with a growth advantage, resulting in expansion of the clone and potential for leukemic transformation.

To identify the cell of origin in 5q− syndrome, Nilsson et al. (30) purified pluripotent hematopoietic stem cells (CD34 + CD38 − ) from MDS patients with a 5q deletion between bands 5q13 and 5q33. These included patients with 5q− syndrome. Virtually all (>90%) CD34 + CD38 − cells belonged to the 5q− deleted clone, indicating that a lymphomyeloid hematopoietic stem cell is the primary target of 5q deletions in MDS and that 5q deletions represent an early event in MDS pathogenesis (30). Notably, although a pluripotent hematopoietic stem cell is the primary target of 5q deletions, mature lymphocytes do not seem to be involved in the 5q− clone, suggesting that the transformed pluripotent stem cell lacks the ability to differentiate toward lymphocytes (30).

Cellular distribution of 5q31 deletion within the bone marrow in 5q− syndrome. In bone marrow smears of patients with 5q− syndrome, the 5q31 deletion is found in all three principal hematopoietic lineages (erythroblasts, granulocyte precursors, and megakaryocytes refs. 30, 31). This is consistent with transformation of a pluripotent stem cell, described above, retaining the ability to proceed along multiple differentiation pathways (30, 31). Bigoni et al. (31) found that despite the fact that all erythrocytes in bone marrow smears of patients with 5q− syndrome were consistently macrocytic, the 5q31 deletion was observed in only 35% to 50% of erythroblasts. The presence of the 5q31 deletion in only a portion of the erythroblasts indicates a mosaicism of cytogenetically altered and normal cells in the bone marrow. This mosaicism was found across all three lineages in 5q− syndrome and seems to be a general phenomenon in MDS (31).

Effect of 5q deletion on bone marrow dysfunction. Ineffective hematopoiesis in MDS is due primarily to excessive apoptosis of hematopoietic progenitors and their progeny in the bone marrow (7, 32). Increased rates of apoptosis in MDS may be triggered by intrinsic cellular mechanisms or by a cytokine/growth factor imbalance in the local environment. In 5q− syndrome and other forms of MDS with 5q deletion, the underlying genetic abnormality itself can give rise to aberrant cytokine production and inappropriate signaling due to deletion of one or more of the corresponding genes (7). Cytokine imbalance in the bone marrow can have broad effects on hematopoiesis by impairing cellular development and function regardless of whether specific cells harbor the 5q deletion. Indeed, dysplastic features can be found in all three major lineages in patients with 5q deletions (18, 31).

However, bone marrow dysfunction in MDS patients with 5q deletions may be less pronounced than in other forms of MDS. Washington et al. (33), for example, found significantly lower rates of apoptosis in bone marrow cells isolated from patients with 5q− syndrome versus patients with other refractory anemias. They hypothesized that lower apoptosis in 5q− syndrome may explain the milder clinical course of the disease and distinguish 5q− syndrome from other MDS. Furthermore, Lopez-Holgado et al. (34) found a higher proportion of myeloid-committed progenitors in patients with 5q deletions compared with MDS patients with trisomy 8 or normal karyotype. Moreover, these myeloid-committed progenitors from patients with 5q deletions were less impaired as indicated by higher plating efficiencies in long-term bone marrow cultures compared with progenitors from patients with normal karyotype or monosomy 7. Together, these observations suggest a lesser degree of functional impairment with respect to hematopoiesis in MDS patients with 5q deletions versus other chromosomal abnormalities.


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Background

Cancer forms through the stepwise acquisition of somatic genetic alterations, including point mutations, copy-number changes, and fusion events, that affect the function of critical genes regulating cellular growth and survival [1]. The identification of oncogenes and tumor suppressor genes being targeted by these alterations has greatly accelerated progress in both the understanding of cancer pathogenesis and the identification of novel therapeutic vulnerabilities [2]. Genes targeted by somatic copy-number alterations (SCNAs), in particular, play central roles in oncogenesis and cancer therapy [3]. Dramatic improvements in both array and sequencing platforms have enabled increasingly high-resolution characterization of the SCNAs present in thousands of cancer genomes [4–6].

However, the discovery of new cancer genes being targeted by SCNAs is complicated by two fundamental challenges. First, somatic alterations are acquired at random during each cell division, only some of which ('driver' alterations) promote cancer development [7]. Selectively neutral or weakly deleterious 'passenger' alterations may nonetheless become fixed whenever a subclone carrying such alterations acquires selectively beneficial mutations that promote clonal dominance [8]. Second, SCNAs may simultaneously affect up to thousands of genes, but the selective benefits of driver alterations are likely to be mediated by only one or a few of these genes. For these reasons, additional analysis and experimentation is required to distinguish the drivers from the passengers, and to identify the genes they are likely to target.

A common approach to identifying drivers is to study large collections of cancer samples, on the notion that regions containing driver events should be altered at higher frequencies than regions containing only passengers [4, 6, 7, 9–14]. For example, we developed an algorithm, GISTIC (Genomic Identification of Significant Targets in Cancer) [15], that identifies likely driver SCNAs by evaluating the frequency and amplitude of observed events. GISTIC has been applied to multiple cancer types, including glioblastoma [10, 15], lung adenocarcinoma [16], melanoma [17], colorectal carcinoma [18], hepatocellular carcinoma [19], ovarian carcinoma [20], medulloblastoma [21], and lung and esophageal squamous carcinoma [22], and has helped identify several new targets of amplifications (including NKX2-1 [16], CDK8 [18], VEGFA [19], SOX2 [22], and MCL1 and BCL2L1 [4]) and deletions (EHMT1 [21]). Several additional algorithms for identifying likely driver SCNAs have also been described [23–25] (reviewed in [26]).

Yet, several critical challenges have not yet been adequately addressed by any of the existing copy-number analysis tools. For example, we and others have shown that the abundance of SCNAs in human cancers varies according to their size, with chromosome-arm length SCNAs occurring much more frequently than SCNAs of slightly larger or smaller size [4, 27]. Therefore, analysis methods need to model complex cancer genomes that contain a mixture of SCNA types occurring at distinct background rates. Existing copy-number methods have also used ad hoc heuristics to define the genomic regions likely to harbor true cancer gene targets. The inability of these methods to provide a priori statistical confidence has been a major limitation in interpreting copy-number analyses, an important problem as end-users typically use these results to prioritize candidate genes for time-consuming validation experiments.

Here we describe several methodological improvements to address these challenges, and validate the performance of the revised algorithms in both real and simulated datasets. We have incorporated these changes into a revised GISTIC pipeline, termed GISTIC 2.0.


FAQs About Chromosome Disorders

What are chromosomes?
Chromosomes are organized packages of DNA found inside your body's cells.[1] Your DNA contains genes that tell your body how to develop and function. Humans have 23 pairs of chromosomes (46 in total). You inherit one of each chromosome pair from your mother and the other from your father. Chromosomes vary in size. Each chromosome has a centromere, which divides the chromosome into two uneven sections. The shorter section is called the p arm, and the longer section is called the q arm.[1][2] MedlinePlus Genetics has a helpful picture of a chromosome.


Are there different types of chromosomes?
Yes, there are two different types of chromosomes sex chromosomes and autosomal chromosomes. The sex chromosomes are the X and Y chromosomes. They determine your gender (male or female). Females have two X chromosomes, XX, one X from their father and one X from their mother. Males have one X chromosome from their mother and one Y chromosome, from their father, XY. Mothers always contribute an X chromosome (to either their son or daughter). Fathers can contribute either an X or a Y, which determines the gender of the child. The remaining chromosomes (pairs 1 through 22) are called autosomal chromosomes. They contain the rest of your genetic information.[1][2][3][4]


What are the different types of chromosome disorders?
Chromosome disorders can be classified into two main types numerical and structural. Numerical disorders occur when there is a change in the number of chromosomes (more or fewer than 46). Examples of numerical disorders include trisomy, monosomy and triploidy. Probably one of the most well-known numerical disorders is Down syndrome (trisomy 21).[1][2] Other common types of numerical disorders include trisomy 13, trisomy 18, Klinefelter syndrome and Turner syndrome.

Structural chromosome disorders result from breakages within a chromosome. In these types of disorders there may be more or less than two copies of any gene. This difference in number of copies of genes may lead to clinical differences in affected individuals. Types of structural disorders include the following: [1][2] (click on each type to view an illustration)

    , sometimes known as partial monosomies, occur when a piece or section of chromosomal material is missing. Deletions can occur in any part of any chromosome. When there is just one break in the chromosome, the deletion is called a terminal deletion because the end (or terminus) of the chromosome is missing. When there are two breaks in the chromosome, the deletion is called an interstitial deletion because a piece of chromosome material is lost from within the chromosome. Deletions that are too small to be detected under a microscope are called microdeletions.[1][2][5] A person with a deletion has only one copy of a particular chromosome segment instead of the usual two copies. Some examples of more common chromosome deletion syndromes include cri-du-chat syndrome and 22q11.2 deletion syndrome.
    , sometimes known as partial trisomies, occur when there is an extra copy of a segment of a chromosome. A person with a duplication has three copies of a particular chromosome segment instead of the usual two copies. Like deletions, duplications can happen anywhere along the chromosome.[1][2][5] Some examples of duplication syndromes include 22q11.2 duplication syndrome and MECP2 duplication syndrome.
    occur when a chromosome segment is moved from one chromosome to another. In balanced translocations, there is no detectable net gain or loss of DNA.[1][2][5]
    occur when a chromosome segment is moved from one chromosome another. In unbalanced translocations, the overall amount of DNA has been altered (some genetic material has been gained or lost).[1][2][5]
    occur when a chromosome breaks in two places and the resulting piece of DNA is reversed and re-inserted into the chromosome. Inversions that involve the centromere are called pericentric inversions inversions that do not involve the centromere are called paracentric inversions.[1][2][5]
    are abnormal chromosomes with identical arms - either two short (p) arms or two long (q) arms. Both arms are from the same side of the centromere, are of equal length, and possess identical genes. Pallister-Killian syndrome is an example of a condition resulting from the presence of an isochromosome.[2][5]
    result from the abnormal fusion of twp chromosome pieces, each of which includes a centromere.[5]
    form when the ends of both arms of the same chromosome are deleted, which causes the remaining broken ends of the chromosome to be "sticky". These sticky ends then join together to make a ring shape. The deletion at the end of both arms of the chromosome results in missing DNA, which may cause a chromosome disorder. MedlinePlus Genetics provides a diagram of the steps involved in the formation of a ring chromosome.[1][2][5] An example of a ring condition is ring chromosome 14 syndrome.

What causes chromosome disorders?
The exact cause is unknown, but we know that chromosome abnormalities usually occur when a cell divides in two (a normal process that a cell goes through). Sometimes chromosome abnormalities happen during the development of an egg or sperm cell (called germline), and other times they happen after conception (called somatic). In the process of cell division, the correct number of chromosomes is supposed to end up in the resulting cells. However, errors in cell division, called nondisjunction, can result in cells with too few or too many copies of a whole chromosome or a piece of a chromosome,[1][6] Some factors, such as when a mother is of advanced maternal age (older then 35 years), can increase the risk for chromosome abnormalities in a pregnancy.[1]


What is mosaicism?
Mosaicism is when a person has a chromosome abnormality in some, but not all, cells. It is often difficult to predict the effects of mosaicism because the signs and symptoms depend on which cells of the body have the chromosome abnormality.[2][7] MedlinePlus Genetics provides a diagram of mosaicism.


How are chromosome disorders diagnosed?
Chromosome disorders may be suspected in people who have developmental delays, intellectual disabilities and/or physical abnormalities. Several types of genetic tests can identify chromosome disorders:

What signs and symptoms are associated with rare chromosome disorders?
In general, the effects of rare chromosome disorders vary. With a loss or gain of chromosomal material, symptoms might include a combination of physical problems, health problems, learning difficulties and challenging behavior. The symptoms depend on which parts of which chromosomes are involved. The loss of a segment of a chromosome is usually more serious than having an extra copy of the same segment. This is because when you lose a segment of a chromosome, you may be losing one copy of an important gene that your body needs to function.[2]

There are general characteristics of rare chromosomal disorders that occur to varying degrees in most affected people. For instance, some degree of learning disability and/or developmental delay will occur in most people with any loss or gain of material from chromosomes 1 through 22. This is because there are many genes located across all of these chromosomes that provide instructions for normal development and function of the brain.[2] Health providers can examine the chromosome to see where there is a break (a breakpoint). Then they can look at what genes may be involved at the site of the break. Knowing the gene(s) involved can sometimes, but not always, help to predict signs and symptoms.


Can chromosome disorders be inherited?
Although it is possible to inherit some types of chromosomal disorders, many chromosomal disorders are not passed from one generation to the next. Chromosome disorders that are not inherited are called de novo , which means "new".[6] You will need to speak with a genetics professional about how (and if) a specific chromosome disorder might be inherited in your family.

How can I find individuals with the same chromosome disorder?
Chromosome Disorder Outreach (CDO) provides information on chromosomal conditions and family matching. Contact CDO for more information about how to connect with other families.

Chromosome Disorder Outreach
PO Box 724
Boca Raton, FL 33429
Family Helpline: 561-395-4252
E-mail: [email protected]
Web site: http://www.chromodisorder.org

Unique is a source of information and support for families and individuals affected by rare chromosome disorders. This organization is based in the United Kingdom, but welcomes members worldwide. Unique also has a list of Registered Chromosome Disorders.

Unique - Rare Chromosome Disorder Support Group
United Kingdom
Telephone: 440 1883 330766
E-mail: [email protected]
Web site: http://www.rarechromo.org


How can I find research studies for individuals with chromosome disorders?
The National Institute of General Medical Sciences (NIGMS) Human Genetic Cell Repository was established in 1972 to provide a readily accessible, centralized resource for genetic material from individuals with inherited defects in metabolism, chromosomal abnormalities, and other genetic disorders. This biobank creates cell lines, DNA and other materials from blood or tissue samples and makes these important resources available to scientists worldwide to facilitate research on the diagnosis, treatment and prevention of rare disorders. They are interested in collecting samples from individuals with chromosome disorders, including but not limited to: rare trisomies, ring chromosomes, micro deletion/duplication syndromes, and balanced and unbalanced translocations or inversions. Click on the link to learn more about this service.

The Developmental Genome Anatomy Project (DGAP) is a research effort to identify apparently chromosomal rearrangements in patients with multiple congenital anomalies and then to use these chromosomal rearrangements to map and identify genes that are disrupted or dysregulated in critical stages of human development. Click on the link to learn more about this study.

Chromosome Disorder Outreach provides information about latest research articles for chromosome disorders.


When might it be appropriate to speak with a genetics professional?
Individuals or families who are concerned about an inherited condition may benefit from a genetics consultation. The MedlinePlus Genetics Web site provides a list of reasons why a person or family might be referred to a genetics professional.

For more information on a specific chromosome abnormality, we encourage you to speak with a genetics professional. Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members.